The invention relates to a bone anchoring device in particular to a bone anchoring device which can be used for stabilization of the spine in the sacro-iliac region.
Stabilization of the spine in the sacro-iliac region requires in certain constellations that the bone screw which is to be connected with the spinal stabilization rod is screwed laterally into the bone.
U.S. Pat. No. 6,981,973 discloses a low profile vertebral alignment/fixation assembly which comprises a hemispherical headed pedicel screw disposed within a slotted coupling unit designed to allow angular adjustment of the pedicle screw up to 90° and which may be locked into position via a single internal locking nut once a rod has been inserted into the slotted coupling unit. The nut has an engagement portion designed to engage the rod. The head of the screw is locked by the action of the rod pressing onto the head. The assembly can be anchored in the ileum bone with the screw aligned at a 90° angle with reference to the coupling unit.
US 2005/0159750 A1 discloses a bone anchor assembly comprising a bone anchor and a receiving member for receiving a spinal rod. The bone anchor can be adjusted in the receiving member such that the longitudinal axis of the bone anchor is at an angle of 0° to 90° relative to the receiving member in a plane which contains the longitudinal axis of the spinal rod. A main application of this anchor assembly is the stabilization of the cervical spine where it can be necessary to pivot the bone anchors out of an alignment to avoid interference due to their close proximity.
US 2005/0154391 A1 discloses a bone anchor assembly comprising a bone anchor and a receiving member to receive a spinal rod. The receiving member has a first section and a second section which is coupled to the bone anchor. The second section is movably connected to the first section. The bone anchor may be adjusted such that the longitudinal axis of the bone anchor is at an angle of 0° to 90° relative to the receiver member.
U.S. Pat. No. 6,736,820 discloses a bone screw having a screw member with a threaded section and a head and a receiving part for receiving a rod to be connected to the bone screw. The receiving part has an open first bore and a substantially U-shaped cross-section to receive the rod and a second bore on the opposite end with a seat for the head. In order that the screw member can be pivoted to at least one side by an enlarged angle, the edge bounding the free end of the second bore is of asymmetric construction.
US 2003/0055426 A1 discloses a biased angulation bone fixation assembly including and anchoring element and a coupling element having a first bore coaxial with a first longitudinal axis and a second bore coaxial with a second longitudinal axis wherein said first and second longitudinal axes are transverse to one another. The coupling element also includes rod receiving openings for receiving a spinal rod.
Based on the above, there is a need to provide an improved bone anchoring device which allows a lateral fixation of the bone anchoring element in the bone, e.g., at an angle of at least 90° relative to the receiving part in a plane perpendicular to the longitudinal axis of the spinal rod which is suitable for use in the sacro-iliac region of the spine.